The subject matter herein relates generally to electrical connector systems.
Some electrical connector systems utilize electrical connectors to interconnect two circuit boards, such as a motherboard and daughter card. Signal loss and/or signal degradation is a problem in known electrical systems. For example, crosstalk results from an electromagnetic coupling of the fields surrounding an active conductor (or differential pair of conductors) and an adjacent conductor (or differential pair of conductors). The strength of the electromagnetic coupling generally depends on the separation between the conductors, such that crosstalk may be significant when the electrical connectors are placed in close proximity to each other. Moreover, as speed and performance demands increase, known electrical connectors are proving to be insufficient. Additionally, there is a desire to increase the density of electrical connectors to increase throughput of the electrical system, without an appreciable increase in size of the electrical connectors, and in some cases, with a decrease in size of the electrical connectors. Such an increase in density and/or reduction in size causes further strains on performance.
In order to address performance, some electrical connectors have been developed that utilize shielding between pairs of signal contacts. The shielding is provided in both connectors along the signal lines, such as through ground contacts. Typically, the individual shields are electrically commoned in both circuit boards. However, the shields remain electrically independent between the circuit boards. The signal lines may experience degradation, such as resonance noise, along their lengths through the electrical connectors. The resonance noise is due to standing electromagnetic waves created at the ends of the ground contacts that propagate along the ground contacts and cause the electrical potential of the ground contact to vary along the length, referred to as resonance spikes. The resonance noise can couple to the pairs of signal contacts to degrade the signal performance. The resonance noise and crosstalk between pairs of signal contacts increases as the electrical connectors are used to convey more data at faster data rates and transmitted at higher frequencies. The resonance noise also increases as the length of the ground contacts between grounding locations increases.
A need remains for an electrical connector that reduces resonance noise to improve signal performance of an electrical connector system.